I. Field of the Disclosure
The technology of the disclosure relates generally to a universal serial bus (USB).
II. Background
Mobile communication devices have become increasingly common in current society. The prevalence of these mobile communication devices is driven in part by the many functions that are now enabled on such devices. Increased processing capabilities in such devices means that mobile communication devices have evolved from being purely communication tools into sophisticated mobile entertainment centers, thus enabling enhanced user experiences.
Peripheral devices, such as audio headsets and portable audio speakers, are often attached to the mobile communication devices for convenience and/or improved audio-playing experience. A universal serial bus (USB) interface is an increasingly popular standard interface to connect such peripherals both outside and inside the mobile communication devices. When a peripheral device is connected to a mobile communication device via the USB interface, the peripheral device is a USB client and the mobile communication device acts as a USB host. As a result, the peripheral device draws power from the mobile communication device, thus shortening the battery life of the mobile communication device.
Since mobile communication devices are facing increasing challenges to provide more and more processing capabilities with limited power supply, it is critical to minimize power consumptions by the peripheral devices connecting to the mobile communication devices as the USB clients.